Abstract

An experiment was conducted at University of Agricultural Sciences, Dharwad, Karnataka to detect molecular variation in Puccinia sorghi Schw. through molecular tool viz., random amplified Polymorphic DNA (RAPD). In this study, molecular variation in the pathogen served as a guideline for breeding suitable maize varieties against common rust disease which seriously affects maize productivity. It was reported that losses in total yield ranged from 0 in the more resistant entries to nearly 50% in more susceptible entries. Losses in total yield in late-planted sweet corn were 18, 26, and 49% for cv. Sugarloaf (most resistant), cv. Jubilee (intermediate) and cv. Style Pak (most susceptible), respectively. Results revealed that a variety of polymorphic bands were found from the specimens by polymerase chain reaction (PCR) amplification using 10 primers: OPA-19, OPB-08, OPB-15, OPB-17, OPC-08, OPD-07, OPD-13, OPD-18, OPF-02 and OPG-05. These bands were used to construct unweighted pair group method with arithmetic mean (UPGMA) dendogram, which cluster analysis divided the 15 specimens into major 2 groups: Groups A and B. Out of 10 primers used, 3 primers viz., OPA-19 (11.11%), OPB-17 (20%) and OPF-2 (14%) showed polymorphism. The similarity coefficient values revealed that, the least similarity (81%) was between Tamil Nadu-Andhra Pradesh, Haryana-Tamil Nadu and Madhya Pradesh-Haveri isolates. The maximum similarity (100%) was found between Andhra Pradesh-Haryana and Belgaum-Jammu and Kashmir isolates. Bihar isolate formed entirely separate cluster within Group A, whereas Tamil Nadu-Maharashtra and Bijapur-Haveri isolates formed separate clusters within Group A. In Group B, Sikkim, Uttar Pradesh, West Bengal and Bengaluru isolates formed entirely separate clusters, respectively.

Key words: Genetic variability, Zea mays, common rust, Puccinia sorghi, random amplified polymorphic DNA (RAPD).